Can't get it running

[Daniel P. McEntee]

The tickler sticking is a common issue. I have a '77 Hercules 250GS that would never overflow when I depressed the tickler. It took a close inspection and measurement to show that it was never touching the floats. I ordered a replacement assembly from Bing International and it was the same length. I don't remember how I made the extension, but I did extend it and it worked properly, and combined with the choke made it a one or two kick cold starter. But then I ran into the same problem with the return spring sticking. Took a while to cure that but got it fixed. If your carb doesn't have a choke, it does make it a bit more difficult to find the right combination of what it takes to start cold, but is possible. My '75 250 Husky has a Bing with no choke and it requires quite a bit of fuel to start cold, and once it does fire, I sometimes have to depress the tickler to help things out if it's really cold outside. I'll be watching for how it goes from here for you. At this point I would try to get some easy break in time on the engine and get the rings seated and make subtle changes along the way.
  Type at you later,
  Dan McEntee

[Dale Sonnenschein]

I had a 250 penton like yours. It took me a while to find what the bike wanted to get it to start. Sometimes it's the process you go through to start it. As said before, tickle it till gas runs out the over flow. I kicked mine through easily two or three times to bring gas into the cylinder. Then kicked it to start. Good luck, the bike looks great.

73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r

[Blue_Dog]

I think you have a compression or maybe port timing issue. Do have the original piston or is your deal a rebuild ?

[Andreas Piepke]

Hi All,

Indeed i was suspicious abiut the compression myself. I measured the gas pressure and found 165 psi. I think this value is not unreasonable for a re-build engine. Or what pressure would you aim for? Doe this sound too low or too high? The piston is a forged Wiseco from AB. I am assuming it is correct and installed it as such. Maybe I'll measure the compression pressure again this weekend. I'll also try to change the number of disks on the Super Trap.
I'll try out different starting procedures. The before-last video I posted (the one showing the many start attempts) isn't even the whole story. I had to push the bike up and down a hill twice to get it running initially. After that I could kick start it but only with difficulty. The 1981 KTM GS I owned long time ago was difficult to start too.

Thanks for your ideas!

Andreas

[454MRW]

If the bike still is hard to start with using the tickler until fuel runs out the overflow hoses, I suspect weak ignition. Did you sand the paint off the engine mount points on the frame and engine cases to guarantee a good ground? I always run a separate heavy gauge wire from the Motoplat stator plate to the ignition coil mount bracket to eliminate the need to remove paint from the frame and engine cases. You can run one directly to any point on the engine from the coil mount, but I prefer directly to the source...It also helps Motoplat life. This is the #1 reason for poor running and hard starting bikes, with the exception of carb jetting, of course. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Farmjohnny]

Has a leak down test been done yet?
It helps to eliminate so many of the "what ifs".

Michael, you are spot-on, with the bonding jumper!

Tom

[Daniel P. McEntee]

I would say 165 psi is quite good. I have seen as little as 90 psi actually run on some small bikes. The leak down test with either vacuum of pressure tests the whole engine including the crank seals. I'm sure the specs are here in the archives but from memory but when you completely block off the intake and exhaust, if it hold 5 psi for more than 5 or 10 minutes you are good to go. Some guys prefer vacuum, and the same thing applies, if it holds a few inches of vacuum for a certain length of time, you are good to go. If you build a lot of engines, the stuff to do the job is easy to make, and only requires one of those hand vacuum pump brake bleeders from Harbor Freight to supply the vacuum. You may know someone that has the stuff also. But I don't think that is the issue. I think you just need to experiment with starting some more. The weak spark could be a leading contender. Vance Smith here on the POG list and on the VINDURO list does a great job of rebuilding the systems and testing them, and I think he has even figured out how to convert them to 12 volts for the lighting circuits. But the simple grounding like Mike describes can work wonders also.
  Keep us posted,
  Dan McEntee

[454MRW]

I re-read the post from the beginning, because I was sure I had mentioned the ground wire addition, and it was very early mentioned on the first page and Andreas had mentioned that the Motoplat was tested By Penton Imports and the magnets re-magnetized, but no mentions if the grounds were cleaned, and no mentioned was made if he did go ahead and install a ground wire, but stated he would after trying a new plug. A good spark to the eye is not necessarily a good spark under load. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[454MRW]

Oops

[454MRW]

I hate it when that happens, double oops!

[Andreas Piepke]

Hi All,

I do see a spark when I remove the plug. I didn't add a current return cable yet but did measure the resistance from the coil mounting to the engine when Michael pointed this out. I found good continuity then. The coil mounting tabs are not painted and the engine mounting bolts are all new and not corroded. Perhaps at this point I should follow Michael's advice, it's easy enough to do and eliminates one uncertainty. Yes indeed the ignition was load tested and the fly wheel re-magnetized. The ignition itself should be in good shape. I also have a new NGK spark plug of the recommended type.

For this vacuum test is there a description of the procedure somewhere? Do I need to take the carburetor and exhaust off for this so I can seal them?
I just read through the new thread on Super Trap exhaust. I'll certainly try to reduce the number of disks from now 7 to 4.
Just to be clear, I am battling with two different but perhaps related problems: (1) difficulty starting the engine, (2) low engine performance. This thread of posts kind of mixes these two issues.

Thanks for your input!

Andreas

[fischercycle]

HIGH ANDREW, My x wife just told me the reason she left me was because I did not have any SPARK left to kick it hard ENOUGH, TO GET IT STARTED,MAYBE GIVE THAT A TRY,THANKS JAKE

[454MRW]

Andreas,
I feel you are not understanding the grounding of the ignition on the Penton.
The bolts have nothing to do with the ground except to keep the engine tight in the frame. The ground is between the inside of the frame mounts to the outside of the engine cases, and the coil mount to the mounting tab on the frame. Unless you have physically ground off the paint from the inside of those mounts and also on the engine mount bosses, you do not have proper ignition grounding. Period.
Do yourself a favor and install the ground wire from the coil mount bracket, (sand the connections to shiny metal) and run the other to a clean shiny metal point of the engine. you can always run it to the actual stator plate later to even improve the path. Then ride the bike and see if there is a difference with no other changes. It doesn't matter that the ignition is tested or you see a good spark. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Farmjohnny]

As Michael said, just because you can see a spark it means very little. In A&P school we would test plugs that looked fantastic till you added a bit of cylinder pressure and watch them go dead. Same with coils.

Add the jumper.

Tom

[Farmjohnny]

I have some experience with testing under vacuum, but with these I prefer to test under pressure. It exposes the components (seals and such) too the same loads that occur under normal operation.